Automatic volume regulation



Oct. 17, 1933. G ULLNER E AL 1,931,070

I I AUTQMATIC VOLUME REGULATION Filed Sept. 1'7, 1930 INPUT MIPUT INVENTOR GEORG. GULLNER BY ER\CH.1EPLER ATTORNEY Patented Oct. 17, 1933 t I I UNITED STATES PATENT OF I E {AUTOMATIC VOLUME REGULATION I Georg; Gullner and Erich Zepler, Berlin, Ger- (many; assignors to Telefunken Gesellschaft fur Drahtlose Telegraphic m. b- H., BerlirnGermany, a corporation of Germany 'Application September 1930, Serial No, 482,434, and in- Germany;ctober 15, 1929 17 Claims. (01. 179-171) The present inventionrelates to amplifier gain itself, however, as to both its-organization and control, and more particularly'to automatic gain method of operation'willcbest' be understood. by control 1 i r I 3 reference to the followingdescription taken in For automatic signal strength, or volume, v connectionwith the drawing in which we-have 6 regulation (fading regulation or compensation) indicated diagrammatically several circuit organ- 60'- in, receiver equipment, it is customary to use the izations whereby our invention maybe carried Iollowing'arrangement: The incoming radio freinto effect. 1 A quency energy is rectified in a rectifier and flows "In the drawing, i I I through a resistance, the drop of potential across Fig. 1 S WS a Ci cu ying the inven- '10 the latter serving as a biasing potential for any ti e 65.

desired tubes of .the receiver apparatus. -For Figs. 2 a d 3 how modified for s o t e-i larger rectifiers, i. e larger input amplitudahigh Vention. i i grid biasing potentials are then obtained, in other Part OfVtheinOOmiIlg energy is ppl to the words, lower amplification and vice versa, greater d' the ect fiergl a direct amplification in the presence of lower amplitudes. u nt fl win th r thr u h pr du acrossv the 70 The chief drawback of this arrangementconsists m al of a resistance 2 f Potential in thatthe amplification of a tube, inthe preswhich E ut d to va y bia potential ence of small amplitudes, is capable of being vaatllbe 3 Which t t y ly ried only at the ratio of 1:10 lest inaccep'tably heated tube isfemp Theemission current '20 great distortion occur; for, a variation of the or tube 3 is used as the filament heating Current 75 I l fi t of t grid biasing potential i of a tube E of the receiver; Where large'incom feasible only by working upon-the curved part 1 5' p t des a e Concerned. i other of the characteristic where difierent slopes can Whe e the direct cu e t flowing through u 1 be obtained b shifting the working point. If i 'l r ythere i t p'a hi h r n iv ri a plurality of tubes are used simultaneously, the biasing potential in tube 3, and this'results'in a feasible amplification is not'raisedto a higher lower filament heating current for tube E. As? power; on the contrary; since in the' d or a result the amplification of the receiver tube E third tube higher amplitudes are present it' is is diminished. The most essential advantage of possibleto reduce the amplification'for two tubes this arrangement above all resides in that the 30 about 30 fold, and for three tubes about 100 fold; amplification of a tube may be reduced at the 85;

40 of regulation is too small.

without distortions being occasioned. g I ratio 1:1000 without distortionsbeing inciden- Quite apart from distortion, in volume r'egulatall-y caused- On the otherhand in areceiver out-- tion by variation of the grid polarizing potential, fit working with an intermediate frequency the conditions are also dependent upon the quality of heating tube may be changed, and this inde- 35 neutralization. [But this latter condition is not ,pend'ently of the quality of neutralization" -90 true 'where'ver receiver equipment working with Other schemes of automatic fadingregulation' an intermediate'frequency is dealt with, and if the by change of filament heating are asfollows: grid biasing potential of the frequency changer In lieu of the normal 1110i; cathode tube 3, a tube is regulated, but, then in turn, the amount magnetron as shown in Fig. 2 is employed To obviate these drawbacks an automatic volcurrent coming from the rectifier 1 is flowing. ume regulating scheme is'disclosed in the pres- In the presence of fluctuations theem'ission cure ntfinvention which is based upon the regulation rent of the magnetron, and thus the heating of of the heating of the cathode of thecontrolled a tube E of the amplifier arrangementis altered.

tube. It is known in the prior art that by heat- In, the presence of relatively large direct current, 100 I ingc'ontrol the amplification of any tube is vaa larger magnetic field is obtained, and the riable inside wide'limits Without anincidental emission current of the magnetron,; and thus disto t n; e Underlying rea on s t at t e the amplification of the receiver decreases. 51013801 the tube decreases, While the character- Whenever the rectifier current is smaller, c ndi-I through the'magnetizing coil' of which the direct 95 I 'i'stic remains. straight. Circuit schemes'accordtions are reversed. This arrangement offers the 1-05 ing to thisinvention are described in what foladvantage that n di tinct plate battery andno lows. i resistanceare required. Another advantage is The novel features which we believe to be charthat the great slope of the magnetron afiords acteristic of our invention are set forth in vpargood regulation. i

ticularity in theappended claims, the invention According to Fig. 3 the direct current of the 1 rectifier flows by way of a relay 2 which, when While we have indicated and described several systems for carrying our invention into effect, it will be apparent to one skilled in the art that our invention is by no means limited to the particular organization shown and described, but that many modifications may be made without departing from the scope of our invention as set :forth in the appended claims.

What we claim is:

1. In combination, a high frequency amplifier tube including a cathode and a heating source therefor, a rectifier having its input connected with theinput circuit of said amplifier tube, and means connected to the rectifier output and heating source to vary the cathode heating to control the amplifier gain.

2. The method of varying the amplification of a vacuum tube amplifier which consists in pro-.

' ducing a current whose amplitude is proportional to the envelopeof the alternating input energy applied to the tube and in controlling the electron. emissivity of the cathode of the tube in accordance with the amplitude of the current so produced.

3. The method of controlling the amplification of a vacuum tube amplifier which consists in rectifying a portion of the input energy and utilizing the 'direct current component of the rectified energy to determine the emissivity of the tube cathode. r

I 4. The method of operating a translating cir. cuit, including a three-element vacuum tube, which consists in producing a current whose amplitude is proportional to the envelope of the alternating input energy, applied to the tube and in so controlling the cathode emissivity of the vacuum tube in accordance with the amplitude of the current so produced that a predetermined relation between the input energy applied .to the system and, the output energy from the system will be obtained. I

' 5. The method of operating a translating circuit, including a three-element, vacuum tube which consists in producinga current whose amplitude is proportional to the envelope of the alternating input energy applied to the tube and in soycontrolling the cathode emissivity of the tube in'accordance with the amplitude of the cur-.

rent so produced thatthe output energy will be a maximum for a predetermined amplitude of the input energy.

6. The method of operating a translating circuit, including a three-element vacuum tube,

'which consists in applying input energy to the tube, rectifying a portion of the input energy before it is applied to the tube, and so controlling the cathode emissivity of the tube by means ofthe vacuum tube, meansto apply energy variations to said tube, means to produce a current whose am plitude is proportional to the envelope of the alternating energy so applied, and means to ad- 'just the cathode .energizationof said tube in acthe amplitude of the current so cordance with produced.

9. In a translating system, a vacuum tube am plifienmeans to apply alternating currents to the grid circuit of said tube, means controlled by'said valternating current-iorproducing a direct current potential whose value is determined by the am the input circuit of said amplifier, a vacuum tube- V rectifier, means to apply said alternating current to said vacuum tube rectifier, thereby producing rectified direct current, and means to control the emissivity of the cathode of said vacuum tube amplifier in accordance with the amplitude of said rectified direct current. I

11. Ina translating system, a vacuum tube amplifier in accordance with the amplitude of.

said rectified direct current;

12. In; a translating system, a vacuum tube amplifier, meansto apply alternating current to the input circuit of said amplifier, a vacuum tube accordance withthe amplitude: of said rectified direct current. v

13. In a. translating system, a vacuum tube j amplifier, means to apply alternating current to the input circuit of said amplifier, a vacuum tube rectifier, means to apply said alternating current to'said-vacuum tube rectifier,.thereby producing rectified direct current, and means including a magnetron tube to control the emissivityof the cathode of said'vacuum tube amplifier in accordance with the amplitude of said rectifiedv direct current. 1

14. In a translating system, a vacuum tube.

amplifier, means to apply alternating current to the input circuit of said amplifier, a vacuum tube rectifier, means to applysaid alternating current to said vacuum tube rectifier, thereby producing rectified direct current, and means includingzan electro-magnetic relay. device connected with the cathode of said amplifier to control the emissivity of the-cathode of said vacuumtube amplifier "in accordance with the amplitude of said rectified direct current.

15. The method of operating an electrical wave transmission network including an electron discharge tube which consists in producing a current whose amplitude is proportional to the en'- velope of alternating input energy applied to the" tube, and controlling the intensity of emission oi electrons in said tube inversely with the amplirectifier, means to apply said alternating current to the rectifier anode circuit and itscathode and anode connected respectively to the cathode and 'anode circuits of the amplifier to control the emissivity of the cathode of said vacuumtube amplifier in accordance with the amplitude of said rectified direct current.

17. In a translating system, a vacuum tube amplifier; means to apply alternating current to the input circuit mu amplifier, a vacuum tube rectifier, meansto apply said alternating current to said vacuumtube rectifier, thereby producing rectified direct current, and means including a v magnetron tube having its ma gnetizin g 0011 connected to the anodes of the rectifier and ampli-. fier, to control the emissivity of the cathode oi? said 'vacuumtube amplifier in accordance with r t the amplitude of said rectified direct current. i

GEORG GULLNER. v ERICH ZEPLER. 

